Trellis coded modulation (TCM) is a modulation scheme designed through combining an encoding scheme and a modulation scheme, which improves transmission efficiency while minimizing the loss of a frequency width. Dual stream transmission scheme is a transmission scheme for improving transmission efficiency while sustaining backward compatibility with a conventional encoding scheme. That is, the dual stream transmission scheme transmit data stream by interposing a stream encoded by a code having a superior code gain compared to a conventional coding scheme.
Although a TCM encoder using a single stream was introduced, a TCM encoder for dual stream is not developed yet.